Insight into the corrosion failure of mullite thermal insulation materials in carbon monoxide

The service condition of mullite thermal insulation materials is complicated, the effects of carbon deposition are always considered the primary cause of damage to mullite ceramic in carbon monoxide atmosphere. In the present study, mullite thermal insulation material was subjected to a carbon monoxide atmosphere at 1100°C–1400°C. The thermodynamics stability, phase composition, and microstructure of the mullite thermal insulation material were analyzed. Furthermore, the effects of carbon monoxide corrosion on thermal shock resistance and compressive creep behavior at high temperatures were evaluated. The carbon content in the mullite-based insulation material is below 0.02% after treatment at 1100°C–1400°C. After treatment at 1400°C, most areas in the specimen comprised corundum and glass phase, and K, Na, Ca, Mg, and Fe were detected as impurities, leading to the improvement of cold crushing strength after 20 thermal shocks but a remarkable recession in high-temperature compressive creep.